Decal-maps: Real-time Layering of
Decals on Surfaces for Multivariate Visualization

Project 01

We introduce the use of decals for multivariate visualization design. Decals are visual representations that are used for communication; for example, a pattern, a text, a glyph, or a symbol, transferred from a 2D-image to a surface upon contact. By creating what we define as decal-maps, we can design a set of images or patterns that represent one or more data attributes. We place decals on the surface considering the data pertaining to the locations we choose. We propose a (texture mapping) local parametrization that allows placing decals on arbitrary surfaces interactively, even when dealing with a high number of decals. Moreover, we extend the concept of layering to allow the co-visualization of an increased number of attributes on arbitrary surfaces. By combining decal-maps,color-maps and a layered visualization, we aim to facilitate and encourage the creative process of designing multivariate visualizations. Finally, we demonstrate the general applicability of our technique by providing examples of its use in a variety of contexts.

  • Authors: Allan Rocha, Usman Alim, Julio Daniel Silva, and Mario Costa Sousa
  • Conference: IEEE Transactions on Visualization and Computer Graphics.
  • DOI: 10.1109/TVCG.2016.2598866
  • Year: 2017

Illustrative Volume Visualization for Unstructured Meshes Based on Photic Extremum Lines (PELs)

Project 02

Scientific visualization techniques create images attempting to reveal complex structures and phenomena. Illustrative techniques have been incorporated to scientific visualization systems in order to improve the expressiveness of such images. The rendering of feature lines is an important technique for better conveying surface shapes. In this paper, we propose to combine volume visualization of unstructured meshes with direct rendering of illustrated iso surfaces. This is accomplished by extending a GPU-based ray-casting algorithm to incorporate illustration with photic extremum lines, a type of feature lines that captures sudden change of luminance, conveying shapes in a perceptually correct way.

  • Authors: Allan Rocha, Fabio Miranda, and Waldemar Celes
  • Conference: SIBGRAPI - Conference on Graphics, Patterns and Images
  • DOI: 10.1109/SIBGRAPI.2011.20
  • Year: 2011

Colorization and Illumination of 2D Animations Based on a Region-tree Representation

Project 04

Colorization and illumination are key processes for creating animated cartoons. Computer assisted methods have been incorporated in animation/illustration systems to reduce the artists’ workload. This paper presents a new method for illumination and colorization of 2D drawings based on a region- tree representation. Starting from a hand-drawn cartoon, the proposed method extracts geometric and topological information and builds a tree structure, ensuring independence among parts of the drawing, such as curves and regions. Based on this structure and its attributes, a colorization method that propagates through consecutive frames of animation is proposed, combined with an interpolation method that accurately computes a normal mapping for the illumination process. Different operators for curve and region attributes can be applied independently, obtaining different rendering effects.

  • Authors: Renata Nascimento, Fabiane Queiroz, Allan Rocha, Adelailson Peixoto, Tseng Ing Ren, and Vinicius Mello
  • Conference: SIBGRAPI - Conference on Graphics, Patterns and Images
  • DOI: 10.1109/SIBGRAPI.2011.6
  • Year: 2011

ReservoirBench: An Interactive Educational Reservoir Engineering Workbench

Project 03

ReservoirBench is an interactive workbench for educational geological science and engineering tasks. It is designed to facilitate education of novice audiences to teach them basic concepts of reservoir modeling and simulation work flow. Traditional training using lectures and software practice can lead to information overload, and retainability is questionable. As an alternative,we propose a physical workbench that is coupled with digital augmentation for the purpose of learning. We take advantage of the crucial role that spatiality and 3D representations play in petroleum reservoir modeling and allow basic domain concepts to be introduced and explored in a tangible and experiential manner. We describe the design of our prototype and reflect on the findings from our preliminary design critique.

  • Authors: Sowmya Somanath, Allan Rocha, Hamidreza Hamdi, Ehud Sharlin, and Mario Costa Sousa
  • Conference: INTERACT - International Conference on Human-Computer Interaction
  • DOI: 10.1007/978-3-319-22701-6_26
  • Year: 2015

About Me

I am currently a PhD candidate at University of Calgary supervised by Dr. Mario Costa Sousa and Dr. Usman Alim. My main research interests focus on multivariate illustrative/scientific visualization exploring topics related to art, visual design, visual perception, interaction design, rendering and GPU-programming. Previously I had also worked on illustrative volume rendering, seismic visualization, cartoon shading and 2D animation.

Refereed Journal and Conference Publications

  • Fahim H. Khan, Allan Rocha and Usman Alim, Comparative Visualizations of Noisy and Filtered Blood Flow from 4D PC-MRI Cardiac Datasets, in IEEE VIS poster, IEEE, 2017.
  • Allan Rocha, “Visualization of Multivariate Data on Surfaces,” in IEEE VIS’17 Doctoral Colloquium.
  • Allan Rocha, Julio Daniel Silva, Usman Alim, and Mario Costa Sousa, Multivariate Visualization of Oceanography Data Using Decals. Workshop on Visualisation in Environmental Sciences (EnvirVis 2017). Co-located with EuroVis 2017.
  • Allan Rocha, Usman Alim, Julio Daniel Silva, and Mario Costa Sousa, Decal-maps: Real-time Layering of Decals on Surfaces for Multivariate Visualization. IEEE Transactions on Visualization and Computer Graphics (Proceedings of Scientific Visualization 2016). January, 1, 2017. Project Page
  • Sowmya Somanath, Allan Rocha, Hamidreza Hamdi, Ehud Sharlin, and Mario Costa Sousa, ReservoirBench: An Interactive Educational Reservoir Engineering Workbench. Proceedings of the 15th IFIP TC.13 International Conference on Human-Computer Interaction (INTERACT'15). 2015. Bamberg, Germany.
  • Renata Nascimento, Fabiane Queiroz, Allan Rocha, Tseng Ing Ren, Vinicius Mello, and Adelailson Peixoto, Computer-assisted Coloring and Illuminating Based on a Region-tree Structure . SpringerPlus. 2012.
  • Allan Rocha, Fabio Miranda, and Waldemar Celes, Illustrative Volume Visualization for Unstructured Meshes Based on Photic Extremum Lines. In SIBGRAPI — XXIV Conference on Graphics, Patterns and Images. Maceio, Brazil, 2011
  • Renata Nascimento, Allan Rocha, Fabiane Queiroz, Adelailson Peixoto, Tseng Ing Ren, and Vinicius Mello, Colorization and Illumination of 2D Animations Based on a Region-tree Representation. In SIBGRAPI — XXIV Conference on Graphics, Patterns and Images. Maceio, Brazil, 2011.
  • About

    Fall 2016

    CPSC 591/691: Rendering

    Instructor: Mario Costa Sousa

    Fall 2015

    CPSC 591/691: Rendering

    Instructor: Usman Alim